Bimodal molecular weight distribution products and broad molecular weight distribution products of ethylene polymers and copolymers contain two components of different molecular weight, one component having a relatively high molecular weight compared to the second component and designated by the acronym HMW (high molecular weight); the second component being of relatively lower molecular weight than the HMW component and being designated by the acronym LMW (low molecular weight component.) In turn, the HMW and the LMW components can have varying molecular weight distribution. The production of two different molecular weight components is related to the hydrogen response, and thus process conditions of polymerization or copolymerization. By comparison, the molecular weight distribution is dependent on the catalyst per se.
For films produced from high molecular weight polyethylene or copolymers of ethylene and for HIC (household and industrial containers) applications, the resin of ethylene preferably is characterized by gel permeation chromatography (GPC) for molecular weight distribution. Resins suitable for film applications typically show a distinctly bimodal molecular weight distribution, with the LMW and HMW components approximately equal in concentration. A HIC resin is narrower in molecular weight distribution, and is typically characterized with an HMW shoulder.